Export/list the control points of a NURBS
OBJ Format supports nurbs, but Blender writes them as edges by default (since many applications don't support them).

File -> Export -> Wavefront OBJ

Then in the options, enable Write Nurbs. This currently only supports Nurbs splines (not surfaces).



If for some reason you need to access different kinds of curve data, writing nurbs to a text file from Python isn't all that complicated.